Avviso di Seminario - Universita' di Pavia

["Leonardo Bottolo" <lbottolo@eco.unipv.it>]

UNIVERSITA' DEGLI STUDI DI PAVIA
DIPARTIMENTO DI ECONOMIA POLITICA E METODI QUANTITATIVI
DIPARTIMENTO DI MATEMATICA "F.CASORATI"
DOTTORATO DI RICERCA IN MATEMATICA E STATISTICA
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                         AVVISO DI SEMINARIO


Giovedi' 13 marzo, alle ore 15.00, nell'aula del Consiglio di Facolta',
Dipartimento di Economia Politica e Metodi Quantitativi (via San Felice 5,
Pavia)


                           BARBARA VANTAGGI
            (Dipartimento di Metodi e Modelli Matematici,
                           Universita' "La Sapienza")


terra' un seminario dal titolo:


                GRAPHICAL REPRESENTATION OF
           ASYMMETRIC GRAPHOID STRUCTURES




Abstract:

The use of graphs to describe conditional independence structures (the
set of conditional independence statements "X is independent of Y given
Z") induced by an uncertainty measure (e.g. probability) has a long and
rich tradition: one can distinguish three main classical approaches
based on undirected graphs, directed acyclic graphs, or chain graphs.
These graphical structures obey graphoid properties (symmetry,
decomposition, weak union, contraction, intersection). On the other hand,
there are other uncertainty independence models, which do not comply with
the symmetric property, so a recent problem is how to represent asymmetric
graphoid structures. L-separation criterion for directed acyclic l-graphs
and its role in the representation problem of asymmetric graphoids is
discussed. The l-graphs are useful also to describe logical constraints
(e.g. functional dependencies) among the variables. An example of asymmetric
graphoid structure is the conditional independence models induced by a
conditional probability (in the sense of de Finetti). These models are based
on a notion of conditional independence, which avoids all the counter-
intuitive situations related to logical constraints among the variables
and to probability values zero and one.




Durante il seminario sarà offerto ai partecipanti un piccolo rinfresco.


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Per ulteriori informazioni riguardo ai Seminari di Probabilita' e
Statistica e' possibile scrivere a:

lbottolo@eco.unipv.it

oppure consultare la pagina WEB dei seminari:

http://economia.unipv.it/eco-pol/semstat/semstat.htm